# Geometric vs Componentwise Vector Addition

1. Jan 18, 2008

### linie18

1. The problem statement, all variables and given/known data

Which of following sets of conditions (A - F), if true, would show that the expressions 1 and 2 above define the same vector C_vec as expressions 3 and 4?

1. The two pairs of expressions give the same length and direction for C_vec.
2. The two pairs of expressions give the same length and x component for C_vec.
3. The two pairs of expressions give the same direction and x component for C_vec.
4. The two pairs of expressions give the same length and y component for C_vec.
5. The two pairs of expressions give the same direction and y component for C_vec.
6. The two pairs of expressions give the same x and y components for C_vec.

2. Relevant equations

1. C=\sqrt{A^2 +B^2 -2 A B \cos(c)},
2. \phi = \sin^{-1}\left(\frac{B\sin(c)}{C}\right).
3. C_x = A + B\cos(\theta),
4. C_y = B\sin(\theta).

3. The attempt at a solution

I thought it would be one where you knew exactly what the vector was like AF and I don't know what I'm missing.

2. Jan 19, 2008

### Tom Mattson

Staff Emeritus
Haven't you forgotten to include something?

3. Feb 3, 2008